KR20160045598A - Evaporation fuel purge system - Google Patents

Abstract

An evaporated fuel purge system comprises: a fuel tank (10); a canister (12) for absorbing and separating an evaporated fuel discharged from the fuel tank; an inhalation path (210) for an internal combustion engine (2) for mixing the evaporated fuel separated from the canister with the fuel for combustion; a purge path (16) for enabling the canister to be in contact with the inhalation path; an ejector device (14) arranged on the purge path; and fluid driving devices (13, 113). The ejector device includes a nozzle unit (140) for accelerating the external fluid. The fluid driving device transports the outside air corresponding to the external fluid, and is introduced to the inside of the nozzle unit. Provided is an evaporated fuel purge system, which is not required for a flame-retardant structure. A purge pump does not increase the flow resistance of the evaporated fuel.

Description

[0001] EVAPORATION FUEL PURGE SYSTEM [0002]

The present invention relates to an evaporative fuel purge system.

The evaporative fuel purge system has a pump that pumps the evaporative fuel. Such a system is used for a vehicle such as a hybrid vehicle or an idling stop vehicle in which the processing time of evaporative fuel is relatively short, or for a vehicle or a low friction engine vehicle having an engine equipped with a supercharger with a low sound pressure in an intake manifold.

JP 4082004 B2 (corresponding to US 2002/0162457 A1) describes a system in which evaporated fuel is sucked from a canister equipped with a purge pump, and evaporative fuel is delivered to the engine intake passages via a purge control valve. The purge pump is disposed on the pipe through which the evaporative fuel flows.

Since the evaporated fuel pumped by the purge pump passes through the purge pump, a flameproof structure for this purge pump is needed. Furthermore, when the purge pump is stopped, the purge pump itself may become the flow resistance of the evaporated fuel.

It is an object of the present invention to provide an evaporative fuel purge system in which a flameproof structure is not required and the purge pump does not increase the flow resistance of the evaporative fuel.

According to one aspect of the present invention, an evaporative fuel purge system includes: a fuel tank for storing fuel; A canister capable of adsorbing evaporated fuel and desorbing evaporated fuel when the evaporated fuel is discharged from the fuel tank; An intake passage of an internal combustion engine in which evaporated fuel desorbed from the canister is mixed with fuel for combustion; A purge passage connecting the canister to the intake passage; A suction portion disposed in the purge passage for sucking evaporative fuel from the canister by a suction force generated by an external fluid ejected from the nozzle portion, an external fluid ejected from the nozzle portion, An ejector device having a diffuser portion for discharging a mixture of evaporated fuel sucked from a suction portion toward an intake passage; And a fluid drive device for transferring outside air corresponding to the external fluid into the nozzle portion.

Accordingly, the evaporative fuel is sucked from the canister by the suction force of the outside air pumped into the nozzle portion of the ejector apparatus by the fluid drive device. The evaporated fuel is mixed with the outside air in the ejector apparatus, and is conveyed as the mixed fluid toward the intake passage. Therefore, the evaporated fuel does not flow through the fluid drive device but flows inside the purge passage, and the mixed fluid can be supplied to the intake passage.

Therefore, a flameproof structure for the purge pump is unnecessary, and the purge pump does not increase the flow resistance of the evaporated fuel.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings.

1 is a schematic view illustrating a vaporized fuel purge system according to a first embodiment;
2 is a schematic diagram illustrating a vaporized fuel purge system according to a second embodiment;
3 is an enlarged view illustrating a check valve and an intake pipe of the evaporative fuel purge system of the second embodiment;
4 is a flowchart for explaining the processing procedure of the abnormal detection control according to the second embodiment;
5 is a graph illustrating a change in pressure in a pipe forming an object passage;
6 is a graph illustrating a change in power consumption or driving cycle of the purge pump;
7 is a graph illustrating a change in pressure in a pipe forming a target passage;
8 is a schematic view illustrating an evaporative fuel purge system according to a third embodiment;
9 is a flowchart for explaining the processing procedure of the abnormal detection control according to the third embodiment;
10 is a schematic view illustrating a vaporized fuel purge system according to a fourth embodiment;
11 is a flowchart for explaining flow control in which the negative pressure of the intake air by the internal combustion engine and the air pumped by the pump are combined;
12 is a schematic diagram illustrating an evaporative fuel purge system according to a fifth embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, parts corresponding to those described in the preceding embodiments can be given the same reference numerals, and redundant description of the parts can be omitted. Where only a portion of the configuration is described in some embodiments, other preceding embodiments may be applied to other portions of the configuration. Parts can be combined even if they are not explicitly stated that they can be combined with other parts. An embodiment can be combined if it is not damaged by combination, even if it is not explicitly stated that it can be combined with other embodiments.

(First Embodiment)

The evaporative fuel purge system 1 according to the first embodiment is described with reference to Fig. The evaporative fuel purge system 1 supplies HC gas in the fuel adsorbed to the canister 12 to the intake passage 210 of the internal combustion engine 2 and the evaporative fuel is supplied from the fuel tank 10 to the atmosphere . 1, the evaporative fuel purge system 1 includes an intake system of an internal combustion engine 2 having an intake passage 210 and a purge system 220 which supplies an evaporation fuel to the intake system of the internal combustion engine 2, System.

The evaporated fuel introduced into the intake passage 210 is mixed with the combustion fuel supplied to the internal combustion engine 2 from the injector and burned in the cylinder of the internal combustion engine 2. The intake system of the internal combustion engine 2 has an intake pipe 21 connected to an intake manifold 20 which is a part of the intake passage 210 through a throttle valve 23. An air filter (24) is disposed in the intake pipe (21).

In this purge system, the canister 12 is connected to the fuel tank 10 via the steam passage 15, and the intake passage 210 is connected to the canister 12 via the purge passage 16. [ The purge passage 16 includes a first purge passage 16a and a second purge passage 16b. The first purge passage 16a connects the canister 12 to the suction portion 141 of the ejector apparatus 14. [ The second purge passage 16b connects the intake passage 210 to the diffuser portion 142 of the ejector apparatus 14. The purge passage 16 interconnects the first purge passage 16a and the second purge passage 16b and also connects the ejector device 14 connected to the first purge passage 16a and the second purge passage 16b, .

The evaporative fuel purge system 1 has an ejector apparatus 14 and a pump apparatus 13 for pumping air from the outside (hereinafter referred to as "outside air") into the nozzle unit 140 of the ejector apparatus 14. The evaporative fuel purge system 1 can suck the evaporative fuel into the suction portion 141 of the ejector apparatus 14 using air.

The ejector device 14 corresponds to a fluid pump that sucks evaporated fuel due to the negative pressure generated when the external fluid pressurized by the pump device 13 flows inside. The external fluid is, for example, external air. The ejector apparatus 14 includes a nozzle unit 140, a suction unit 141, and a diffuser unit 142. The external air pumped by the pump device 13 flows through the external fluid passage 17. The ejector apparatus 14 is installed in a passage between the external fluid passage 17 and the second purge passage 16b.

The external fluid passage 17 connects the ejector apparatus 14 to the outside of the present system and the air pumped by the pump apparatus 13 flows from the outside into the ejector apparatus 14 through the external fluid passage 17 . The pump device 13 is disposed in the external fluid passage 17. The pump device 13 is, for example, a fluid drive device including a turbine that is rotated by a motor to pump external air to the nozzle portion 140 by sucking outside air. Therefore, the air conveyed by the pump device 13 flows into the ejector device 14 from the nozzle part 140, and causes the suction part 141 to generate negative pressure as the pressurized fluid. Thus, the evaporated fuel is sucked from the suction portion 141 through the first purge passage 16a.

The second purge passage 16b is a fuel outflow passage for introducing a mixed fluid of the evaporated fuel and the outside air passing through the ejector apparatus 14 into the intake passage 210. [ The axial center of the second purge passage 16b can coincide with the axial center of the external fluid passage 17. [

The nozzle unit 140 constitutes a choke passage with respect to the incoming air. The inner diameter of the nozzle portion 140 gradually decreases toward the distal end portion. One end of the choke passage is connected to the external fluid passage 17, and the other end of the choke passage extends toward the second purge passage 16b. The nozzle unit 140 raises the flow rate of air flowing from the outside through the external fluid passage 17 in accordance with the choke effect. Therefore, a negative pressure is generated at the tip of the nozzle unit 140 through which high-speed air flows.

The suction portion 141 is a passage that extends in a direction intersecting with or perpendicular to the nozzle portion 140 and is connected to the tip portion of the nozzle portion 140. The suction portion 141 draws the evaporative fuel from the first purge passage 16a due to the negative pressure in the nozzle portion 140. [

The diffuser portion 142 is the passage downstream of the nozzle portion 140 and the suction portion 141 and the inner diameter is gradually increased as it extends toward the second purge passage 16b. One end of the diffuser portion 142 is connected to the nozzle portion 140 and the suction portion 141 and the other end of the diffuser portion 142 whose diameter is increased is connected to the second purge passage 16b. The diffuser portion 142 reduces the pressure of air and evaporative fuel flowing therein. The axial centers of the nozzle portion 140 and the diffuser portion 142 coincide with the axial centers of the external fluid passage 17 and the second purge passage 16b. That is, the nozzle portion 140, the diffuser portion 142, the external fluid passage 17, and the second purge passage 16b have the same axial center.

When the evaporative fuel is purged, the pump device 13 is operated and the outside air flows into the ejector device 14 from the nozzle part 140 and flows out from the diffuser part 142 to the second purge passage 16b. The evaporated fuel adsorbed in the canister 12 is sucked into the ejector apparatus 14 from the suction section 141 through the first purge passage 16a by the suction action of the ejector apparatus 14 at this time.

The evaporated fuel sucked from the suction portion flows into the cylindrical passage formed in the ejector device 14 at a position between the nozzle portion 140 and the diffuser portion 142. The sucked evaporative fuel is mixed with the air introduced into the diffuser portion 142 from the nozzle portion 140 in the middle of the cylindrical passage and the mixture of the fuel and the air is introduced into the intake passage 210 through the second purge passage 16b . Therefore, the evaporated fuel flowing into the second purge passage 16b from the canister 12 does not flow back toward the pump device 13, and therefore does not pass through the pump device 13. [ The evaporated fuel supplied to the intake passage 210 is introduced into the intake manifold 20 and mixed with the combustion fuel supplied from the injector to the internal combustion engine 2 to be burnt in the cylinder of the internal combustion engine 2 .

The air filter 24 is disposed upstream of the intake pipe 21 for capturing dust contained in the intake air. The throttle valve 23 is an intake air amount control valve interlocked with the accelerator, and adjusts the valve opening degree of the inlet portion of the intake manifold 20 to adjust the intake air amount flowing into the intake manifold 20. The intake air is passed through the air filter 24, the throttle valve 23, and the intake manifold 20 in sequence, mixed with the combustion fuel injected from the injector, burned in the cylinder after a predetermined air / do.

The fuel tank 10 is a container for storing fuel such as gasoline. The fuel tank 10 is connected to the inlet of the canister 12 by a pipe forming the steam passage 15. The canister 12 is a container filled with an adsorbent such as activated carbon and blows evaporative fuel generated in the fuel tank 10 through the vapor passage 15 and temporarily adsorbs the adsorbent on the adsorbent. The canister 12 has a canister closing valve 11 (CCV (11)) for opening and closing a suction portion for blowing outside fresh air. When the canister 12 is provided with the CCV 11, atmospheric pressure can be applied to the canister 12. The canister 12 can easily desorb (purge) evaporated fuel adsorbed on the adsorbent by fresh air.

The canister (12) has an outlet through which the evaporative fuel discharged from the adsorbent flows out. The end of the pipe forming the first purge passage 16a is connected to the outlet. The other end of the pipe forming the first purge passage 16a is connected to the suction portion 141 of the ejector apparatus 14. The purge passage 16 is connected to the first purge passage 16a, the suction portion 141, the diffuser portion 142, and the second purge passage 16b from the canister 12 toward the intake passage 210 of the internal combustion engine. Order.

The control device 3 is an electronic control unit of the evaporative fuel purge system 1. The control device 3 includes a microcomputer having a central processing unit (CPU) for performing arithmetic processing and control processing, a memory such as ROM and RAM, and an I / O port (input / output circuit). The control device 3 performs basic control such as fuel purging in the evaporative fuel purge system 1. For this reason, the control device 3 is connected to the respective actuators of the pump device 13 and the CCV 11 to control the pump device 13 and the CCV 11.

The control device 3 is connected to the motor of the pump device 13. The control device 3 controls the pump device 13 by operating the motor irrespective of the operation / stoppage of the internal combustion engine 2. A signal corresponding to the rotational speed, the intake air amount, and the temperature of the cooling water of the internal combustion engine 2 is inputted to the input port of the control device 3. [

The evaporated fuel sucked into the intake manifold 20 from the canister 12 is mixed with the combustion fuel supplied from the injector to the internal combustion engine 2 and burned in the cylinder of the internal combustion engine 2. [ The air / fuel ratio, which is the mixing ratio of the combustion fuel and the intake air in the cylinder of the internal combustion engine 2, is controlled to a predetermined predetermined air / fuel ratio. The control device 3 controls the output of the fluid pumped by the pump device 13 so that the purge amount of the evaporative fuel is controlled so that the predetermined air / fuel ratio is maintained even if the purge amount of the evaporative fuel is controlled.

Advantages of the evaporative fuel purge system 1 of the first embodiment are described. The evaporative fuel purge system 1 includes a fuel tank 10, a canister 12, an intake passage 210 of the internal combustion engine 2, a purge passage 16, an ejector 14, And a pump device (13) for introducing the gas into the chamber (140). The ejector apparatus 14 includes a nozzle unit 140, a suction unit 141, and a diffuser unit 142, and is located in the middle of the purge passage 16. The suction unit 141 sucks the evaporative fuel from the canister 12 by the suction force of the air ejected from the nozzle unit 140. The air ejected from the nozzle unit 140 and the evaporated fuel sucked from the suction unit 141 are mixed in the diffuser unit 142 and the pressure of the mixed fluid is lowered by the diffuser unit 142, Lt; / RTI >

Therefore, when the pump device 13 pumps the outside air into the nozzle portion 140, a suction force for sucking the evaporation fuel may act on the suction portion 141. [ By this suction force, the evaporative fuel is sucked from the canister 12 and mixed with the outside air blown into the ejector apparatus 14 from the nozzle unit 140 to form a mixed fluid. This mixed fluid can be discharged toward the intake passage 210 after the pressure is lowered.

Therefore, the evaporative fuel purge system 1 can provide a gas supply path for supplying a mixed fluid of outside air and vaporized fuel to the intake passage 210. At this time, the evaporative fuel flows through the purge passage 16, and the evaporative fuel does not pass through the inside of the pump device 13. [ Therefore, with respect to the purge pump for supplying the evaporative fuel in the evaporative fuel purge system 1, the flame retarding structure is unnecessary. Moreover, the purge pump does not increase the flow resistance of the evaporative fuel. It is unnecessary to adopt a flame resistant structure in which the spark does not come into contact with the evaporation fuel, and it is not necessary to use a brushless motor as the motor of the purge pump.

(Second Embodiment)

2 to 6, an evaporative fuel purge system 101 according to a second embodiment will be described. The same structure, function, and effect as those of the first embodiment are not described in the second embodiment.

The evaporative fuel purge system 101 prevents evaporated fuel from being released into the atmosphere after it is generated in the fuel tank 10. [ If a hole is formed in the purge system, there is a risk that the fuel will be released to the atmosphere as a leak of the evaporative fuel purge system. Furthermore, even when an abnormality such as a leak occurs, the driver of the vehicle can not detect an abnormality because the operation of the internal combustion engine 2 is not greatly affected. Therefore, the second embodiment aims at detecting an abnormality of the purge system prematurely.

The evaporative fuel purge system 101 includes a bi-directional rotary pump 113 and a sub-canister 19. [ The bidirectional rotary pump 113 is a fluid drive device having blades rotated in the normal direction and the reverse direction by a motor to transfer the fluid in two mutually opposite directions. The sub-canister 19 has a vessel with an adsorbent, such as activated carbon, that is the same as the canister 12. [ The sub-canister 19 is positioned between the nozzle portion 140 of the ejector device 14 and the bidirectional rotary pump 113, and the evaporative fuel passing through the container is adsorbed on the adsorbent.

The bidirectional rotary pump 113 is a two-way rotary pump. When the blade is rotated in the forward direction, external air is blown and fed toward the nozzle unit 140. When the blade is rotated in the reverse direction, the bidirectional rotary pump 113 blows the fluid in the pipe forming the target passage and transfers it to the outside. In the abnormal detection control, the control device 3 controls the motor of the bidirectional rotary pump 113 to rotate in the reverse direction. When the evaporation fuel is supplied to the intake passage 210, the controller 3 controls the motor of the bidirectional rotary pump 113 so as to rotate in the normal direction.

The evaporative fuel purge system 101 further includes a check valve 4 which is a valve device installed in the end region where the second purge passage 16b and the intake passage 210 of the internal combustion engine 2 are interconnected. The check valve 4 allows fluid to flow into the intake passage 210 from the second purge passage 16b and prevents fluid from flowing backward from the intake passage 210 to the second purge passage 16b. Due to this check valve 4, the evaporative fuel purge system 101 can detect the leakage of the evaporative fuel in the target passageway, which is a specific area within the evaporative fuel purge system 1.

The target pathway is the path through which abnormalities such as holes or discontinuities in the duct or hose are detected in the evaporative fuel purging system 1. Therefore, the object passage is set at least in the second purge passage 16b. Furthermore, the target passage can also be set in the first purge passage 16a since a leak can be detected in the first purge passage 16a in addition to the second purge passage 16b. The range of the target pathway is not limited to the fuel tank 10, the steam passage 15, the canister 12, the ejector device 14, the sub-canister 19, the external fluid passage 17, .

The check valve 4 is installed in the intake pipe 21 as a duct member forming the intake passage 210. 3, the check valve 4 is positioned in the cylindrical end region 21a of the intake pipe 21 having a cylindrical shape extending in a direction crossing the axis of the intake passage 210. As shown in Fig. The check valve 4 completely closes the passage in the cylindrical end region 21a. Therefore, the check valve 4 is not installed in the duct 16bb forming the second purge passage 16b but installed in the intake pipe 21. [ Due to the backflow prevention function of the check valve 4, the entire passage in the duct 16bb can be filled with evaporative fuel. Therefore, if there is a leakage portion such as a hole in any place of the duct 16bb, the evaporated fuel filled in the target passage will necessarily leak. The evaporative fuel purge system 101 has an abnormality detecting function for detecting a leak and determining that an abnormality has occurred in the purge system.

The control device 3 has an abnormality determination circuit 30 that performs basic control such as fuel purging in the evaporative fuel purge system 1 and determines an abnormality in the system as an abnormality determination section. For this reason, the control device 3 is connected to the respective actuators of the bidirectional rotary pump 113 and the CCV 11 to control the bidirectional rotary pump 113 and the CCV 11.

A signal corresponding to the internal pressure of the fuel tank 10 detected by the pressure sensor 18 is input into the input port of the control device 3. [ The evaporative fuel purge system 101 uses the pressure in the fuel tank 10 detected by the pressure sensor 18 to determine an abnormality such as a leak in the passage from the check valve 4 to the fuel tank 10 can do.

The abnormal detection control of the second embodiment will be described with reference to the flowchart of Fig. The control device 3 performs processing according to the flowchart of Fig. This flowchart shows a control for detecting whether or not the passage included in the range of the target passage is in an abnormal state.

This flow chart is operated when the internal combustion engine 2 of the vehicle is stopped. That is, the abnormal detection control of the evaporative fuel purge system 101 is performed periodically in the OFF state of the internal combustion engine 2. [

When the flowchart begins, the control device 3 repeatedly determines whether or not the internal combustion engine 2 has been stopped until it is determined in step S10 that the internal combustion engine 2 is stopped. If it is determined in step S10 that the internal combustion engine 2 has been stopped, the control device 3 controls the bidirectional rotary pump 113 to close the CCV 11 in step S20 and rotate the blade in the reverse direction in step 30 do. The inflow of outside air into the first purge passage 16a is blocked by the canister 12 and the fluid in the purge passage 16 is sucked by the bidirectional rotary pump 113. [ Therefore, the passage included in the range of the target passage becomes the negative pressure state.

At this time, the intake passage 210 and the second purge passage 16b are blocked by the check valve 4, so that the purge passage 16 and the intake passage 210 are not communicated with each other. Since the evaporated fuel sucked by the bidirectional rotary pump 113 is adsorbed by the adsorbent of the sub-canister 19, the evaporated fuel does not pass through the pump and the release to the atmosphere can be suppressed.

The control device 3 keeps this state for a predetermined period of time and sets it to a determinable state in which an abnormality of the target path can be detected. In step S40, the control device 3 acquires the pressure in the object passage blocked from the intake passage 210 by receiving the pressure signal detected by the pressure sensor 18. [

In step S50, the abnormality determination circuit 30 of the control device 3 determines whether or not the abnormal condition is satisfied. The abnormal condition is a condition for determining whether or not an abnormality such as a leak has occurred in the target path in a determinable state.

The evaporative fuel purge system 101 detects a change in the physical quantity related to the pressure change in the object passage, and determines whether the passage is normal or abnormal in step S50. The physical quantity related to the pressure change is a physical quantity showing a specific change in each of the normal state and the abnormal state. For example, the physical quantity is a pressure measured at the periphery of the target passage, the power consumption of the bidirectional rotary pump 113, the consumption current, the consumption voltage, or the number of revolutions, or the change in the reciprocating motion or the driving cycle of the piston. In the case of the number of revolutions of the pump, the time taken at the unit revolution corresponds to the driving period.

In the second embodiment, the abnormality determination is performed using, for example, a change in the pressure detected by the pressure sensor 18. [ The graph of FIG. 5 shows a case in which the pressure is detected by the pressure sensor 18 when the target passage is in a negative pressure state by forcibly discharging the fluid to the outside by the bidirectional rotary pump 113, Fig. In this case, as shown in Fig. 5, the pressure value of the pressure sensor 18 is lowered with the lapse of time at the normal time. The rate of decrease in abnormal conditions is smaller than that in normal cases.

As the physical quantity related to the pressure change in the object passage, a change in the driving period of the bidirectional rotary pump 113, such as the power consumption, the consumption current, or the consumption voltage or the pump rpm, may be used in the evaporative fuel purge system 101. In this case, as shown in Fig. 6, the power consumption of the bidirectional rotary pump 113 is increased over time at normal times. The rate of change at abnormal time is smaller than that at normal time. The consumed current and the consumed voltage have a curve similar to that of FIG. 6 showing the power consumption or the driving period.

When there is no leakage in the target passage in step S50, the pressure of the target passage controlled to be in the negative pressure state is gradually increased by the suction force of the bidirectional rotary pump 113, . On the other hand, when there is a leak in the target passage, the evaporative fuel leaks to the outside, so that even in the state where the suction force acts on the bidirectional rotary pump 113 as shown in the abnormal state in Fig. 5, Does not change much. The abnormal condition in step S50 is established when, for example, the pressure change per unit time (pressure change rate) is smaller than a predetermined first predetermined value. Therefore, the abnormality determination circuit 30 determines that an abnormality exists when the rate of pressure change is less than the first predetermined value. When the rate of pressure change is equal to or larger than the first predetermined value, the abnormality determination circuit 30 determines that the abnormality does not exist.

The abnormal condition in step S50 can be established when the consumed current per unit time (change rate of the consumed current) is less than a predetermined second predetermined value. The abnormality determination circuit 30 determines that an abnormality exists when the rate of change of the consumption current is less than the second predetermined value. When the rate of pressure change is equal to or greater than the second predetermined value, the abnormality determination circuit 30 determines that the abnormality does not exist.

If the abnormality determination circuit 30 determines in step S50 that an abnormal condition is not established, the system is normal. The abnormal detection control is terminated, and the control device 3 proceeds to step S80. In step S80, it is determined whether or not a predetermined time has elapsed after performing step S50. In other words, the process of step S80 is repeatedly performed until the next determination timing arrives. If it is determined in step S80 that the predetermined time has elapsed, the control device returns to step S10 and the processing of the subsequent abnormal detection control is performed again. Thus, the abnormal detection control of the evaporative fuel purge system 101 is repeatedly performed at predetermined time intervals.

If the abnormality determination circuit 30 determines that the abnormality condition is established in step S50, the control device 3 determines that abnormality exists in the target path in step S60. Further, when it is indicated in step S70 that the target path is an abnormal condition, the abnormal detection control is ended, and the flow advances to step S80. The abnormal display is performed by lighting or flashing a predetermined lamp to show that an abnormality exists in the target path, or by displaying an abnormal display on a predetermined screen. Such an abnormal display may be replaced by generating an alarm sound.

The processing of step S50 may be performed by the method described below. If it is determined in step S10 that the internal combustion engine 2 is stopped, the CCV 11 is closed in step S20, and the bidirectional rotary pump 113 is controlled to rotate the blade in the reverse direction in step S30. Then, the bidirectional rotary pump 113 is stopped. At this time, the pressure of the target passage detected by the pressure sensor 18 is changed so that the negative pressure state gradually progresses as shown by the dotted line in Fig. The graph of FIG. 7 shows a case in which the pressure is detected by the pressure sensor 18 when the target passage is in a negative pressure state by forcibly discharging the fluid to the outside by the bidirectional rotary pump 113, Fig. In this case, as shown in FIG. 7, in the abnormal state, since the outside air flows in the passage of time, the pressure value of the pressure sensor 18 changes. Specifically, the degree of sound pressure is reduced. At normal times, the degree of sound pressure is not changed.

Since the bidirectional rotary pump 113 is stopped, the target passages in the negative pressure state are shut off from each other. Therefore, it is assumed that the abnormal condition in step S50 is established, for example, when the pressure change per unit time (pressure change rate) is equal to or greater than a predetermined third predetermined value. The abnormality determination circuit (30) determines that an abnormality exists when the rate of pressure change is equal to or greater than the third predetermined value. When the rate of pressure change is less than the third predetermined value, the abnormality determination circuit 30 determines that the abnormality does not exist.

Advantages of the evaporative fuel purge system 101 of the second embodiment are described. The evaporative fuel purge system 101 includes a bidirectional rotary pump 113 that is capable of sucking fluid from the purge passage 16 to the outside. In other words, the bidirectional rotary pump 113 is a fluid drive device that uses two blades rotated by a motor in a normal direction and a reverse direction to transfer fluid from two mutually opposite directions.

Further, the evaporative fuel purge system 101 allows the evaporated fuel discharged from the diffuser portion 142 to flow into the intake passage 210 from the purge passage 16 and flows from the intake passage 210 to the purge passage 16, And a check valve 4 for preventing the fluid from flowing backward.

The evaporative fuel purge system 101 further includes an abnormality determination circuit 30 that determines an abnormality such as a leak in the purge passage 16 in a state in which the bidirectional rotary pump 113 sucks the fluid of the purge passage 16 . The abnormality determination circuit 30 detects a predetermined physical quantity related to the pressure change in the object passage including the purge passage 16 and determines an abnormality in the system in accordance with the detected physical quantity.

Therefore, by the backflow prevention function of the check valve 4 and the suction force of the bidirectional rotary pump 113, the leakage generated in the purge passage 16 is determined according to the detection value of the predetermined physical quantity related to the pressure change in the passage . This allows the purge system to detect an abnormality in the purge passage 16 that is wide enough to reach the end region connected to the intake passage 210. [

The evaporative fuel purge system 101 can complete the abnormality determination processing in a short time by controlling the output of the bidirectional rotary pump 113. [

The evaporative fuel purge system 101 includes a sub-canister 19 that absorbs evaporative fuel contained in the fluid of the purge passageway 16 that is drawn by the bidirectional rotary pump 113. Therefore, the evaporated fuel may be discharged to the atmosphere by passing through the pump by the suction force of the bidirectional rotary pump 113, but the evaporated fuel can be adsorbed by the sub-canister 19 when judging the abnormality. Therefore, the evaporative fuel purge system 101 can control the diffusion of HC gas in the fuel into the atmosphere by using a pump having no flame-proof structure.

The check valve 4 is installed in the intake pipe 21 as a duct member forming the intake passage 210 instead of the duct 16bb forming the purge passage 16. [ The check valve (4) is indirectly attached to the purge passage (16). When the check valve 4 exhibits the backflow prevention function, the entire purge passage 16 can be a space closed by the check valve 4. [ Thus, the entire purge passage 16 can be filled with evaporative fuel. Therefore, an abnormality can be determined with respect to the entire purge passage 16.

The predetermined physical quantity used for determining the abnormality by the abnormality determination circuit 30 is the internal pressure of the fuel tank 10. [ The abnormality of the purge passage 16 can be determined using the detection value of the pressure sensor 18 mounted to detect the internal pressure of the fuel tank 10. [

The predetermined physical quantity used for determining the abnormality by the abnormality determination circuit 30 is at least one of the power consumption, the current consumption, the consumption voltage, and the number of revolutions of the bidirectional rotary pump 113. The abnormality determination circuit (30) determines an abnormality in accordance with a change of a predetermined physical quantity. Since the pressure change in the target path acts as a resistor on the bidirectional rotary pump 113, the abnormality determination circuit 30 can detect the change in the drive cycle such as power consumption or pump revolution as information related to the load of the bidirectional rotary pump 113 . A change in the driving period such as the power consumption or the pump rotational speed can be easily obtained. Therefore, the abnormality determination circuit 30 can detect important information related to the pressure change in the object passage without directly measuring the pressure in the duct forming the object passage. Therefore, the number of members of the system can be reduced since a sensor for detecting the pressure in the duct becomes unnecessary.

(Third Embodiment)

The evaporative fuel purge system 201 according to the third embodiment will be described with reference to Figs. 8 and 9. Fig. In the third embodiment, the same structure, function, and effect as the above embodiment are not described.

The evaporative fuel purge system 201 includes a concentration detector 5 for detecting the concentration of evaporative fuel in the fuel-air mixture of the air purged into the intake passage 210 and the evaporative fuel. The density detector 5 is described below. The concentration detector 5 includes a differential pressure sensor, a sub-canister, a first electromagnetic valve, a second electromagnetic valve, a choke portion, a first detection passage, a second detection passage, and an atmospheric air passage.

One end of the first detection passage is connected to the middle of the purge passage 16. And the other end of the first detection passage is connected to one end of the second detection passage through the second electromagnetic valve. And the other end of the second detection passage is opened to the atmosphere through an air filter. One end of the target passage is connected to the second electromagnetic valve. The other end of the target passage is opened to the atmosphere through an air filter. The choke portion is formed between the second electromagnetic valve and the air filter in the second detection passage.

The second electromagnetic valve is a three-way electromagnetic valve. In accordance with the control signal output from the control device 3, the choke portion communicates with the atmosphere so that the second detection passage communicates with the atmospheric passage. Alternatively, the choke portion may be communicated with the first detection passage so that the first detection passage communicates with the second detection passage.

The sub-canister is positioned between the choke section and the air filter. A first electromagnetic valve is disposed between the sub-canister and the choke portion. The first electromagnetic valve is a closed bi-directional electromagnetic valve. According to the control signal outputted from the control device 3, the choke part is communicated with or disconnected from the sub-canister.

A pump is disposed between the air filter and the sub-canister. The sub-canister, like the canister 12, contains an adsorbent such as activated carbon. When the pump is operated to depressurize the second detection passage with the first detection passage and the second detection passage communicated with each other, the evaporated fuel adsorbed on the canister 12 is sucked into the second detection passage. When the fuel-air mixture passes through the sub-canister, the sub-canister adsorbs the evaporative fuel to remove the evaporative fuel from the fuel-air mixture. For this reason, while the fuel-air mixture passes through the choke portion, the differential pressure sensor detects the pressure of the air passing through the choke portion.

The differential pressure sensor is disposed in a passage connecting the target passage to the second detection passage between the pump and the sub-canister, and detects the pressure in the choke portion. The differential pressure sensor detects a differential pressure between the pressure in the second detection passage between the pump and the choke portion and the atmospheric pressure in the object passage connected to the atmosphere through the air filter. Therefore, the differential pressure detected by the differential pressure sensor during the operation of the pump is substantially equal to the differential pressure between the opposite ends of the choke portion with the first electromagnetic valve opened. With the first electromagnetic valve closed, the second detection passage is closed at the suction side of the pump, so that the differential pressure detected by the differential pressure sensor during the operation of the pump is substantially equal to the shutoff pressure of the pump.

The control device 3 calculates the concentration of the evaporated fuel in the fuel-air mixture purged into the intake passage 210 based on the pressure detection signal output from the differential pressure sensor of the concentration detector 5. [ Furthermore, the control device 3 controls the fuel injection amount injected from the fuel injection valve in accordance with the air / fuel ratio detected by the air / fuel ratio sensor and the concentration of the calculated evaporated fuel.

The control device 3 stores the density of the air and the density of the gas in the case where the concentration of the evaporative fuel is 100% in advance in the memory. The control device 3 calculates a predetermined operation (air-fuel ratio) using the density of the air, the density of the gas (that is, the evaporation fuel) when the concentration of the evaporative fuel is 100% To calculate the concentration of the evaporated fuel.

The shut-off pressure is detected by the differential pressure sensor when the pump is operated to depressurize the second detection passage and the second electromagnetic valve is closed. The air pressure is detected by a differential pressure sensor when the pump is operated to depressurize the second detection passage and the first electromagnetic valve is opened and the second detection passage and the object passage are communicated by switching of the second electromagnetic valve . When the fuel-air mixture passes through the choke portion, the pressure of the fuel-air mixture is reduced by operating the pump to depressurize the second detection passage, and the second electromagnetic valve is opened so that the second detection passage and the first detection passage are closed And is detected by the differential pressure sensor while being communicated by switching of the electromagnetic valve.

The abnormality detection control of the third embodiment will be described with reference to the flowchart of Fig. The control device 3 performs processing according to the flowchart of Fig. This flow chart shows a control for detecting whether or not the steam passage 15, the first purge passage 16a, and / or the second purge passage 16b are in an abnormal state.

In the abnormal detection control of the evaporative fuel purge system 1, when the execution condition of the abnormality determination is established in step S120, the abnormality determination based on this flowchart is executed in step S160.

When the flowchart starts, the control device 3 acquires data in step S100, and this data is used for operation in step S110. The various data detected in step S100 include the data provided by the density detector 5, the detection signal provided by the differential pressure sensor, and the detection signal provided by the pressure sensor 18.

The control device 3 performs a process of calculating the concentration of evaporated fuel or the remaining amount of evaporated fuel in the canister in step S110. The concentration of the evaporative fuel is calculated by the above-described method using the concentration detector 5.

The remaining amount of evaporated fuel in the canister is the amount of evaporated fuel remaining in the canister 12 and can be calculated by subtracting the amount of purge from the amount of evaporated fuel generated from the fuel tank 10. [ The amount of purge is calculated using the concentration of evaporative fuel. The amount of evaporative fuel generated from the fuel tank 10 is calculated by using the difference of the fuel temperature (for example, the difference of the fuel temperature per unit time), the empty space of the fuel tank 10, and the internal pressure of the fuel tank 10 . Alternatively, the amount of evaporative fuel generated from the fuel tank 10 may vary between the actual purge amount and the theoretical value calculated from the canister desorption performance characteristic (e.g., the relationship between the aeration amount of the canister and the desorption amount of the canister) The difference is calculated. The desorption amount of the canister can be calculated based on the aeration amount of the canister using the canister desorption performance characteristic.

The control device 3 determines in step S120 whether or not the execution condition of the abnormality determination is established. The execution condition is a condition that is set to determine whether or not the abnormality determination process should be executed in order to determine an abnormality in the object path in the determinable state. The target passage includes a vapor passage 15, a first purge passage 16a, a second purge passage 16b, a concentration detector 5, a fuel tank 10, a canister 12, an ejector device 14, A passageway 17, and a bi-directional rotary pump 113.

In step S120, it is determined whether or not the concentration of the evaporated fuel calculated in step S110 is lower than a predetermined first threshold value. When the concentration of the evaporative fuel is equal to or less than the first threshold value, it is determined that the execution condition of the abnormality determination is established, and the process proceeds to step S130. When the concentration of the evaporative fuel exceeds the first threshold value, it is determined that the execution condition of the abnormality determination is not established, and the process returns to step S100.

Alternatively, in step S120, it is determined whether or not the remaining amount of the evaporated fuel in the canister is equal to or less than a predetermined second limit value by using the concentration of the evaporated fuel calculated in step S110. When the remaining amount of the evaporated fuel in the canister is equal to or less than the second threshold value, it is determined that the execution condition of the abnormality determination is established, and the process proceeds to step S130. When the remaining amount of the evaporated fuel in the canister exceeds the second threshold value, it is determined that the execution condition of the abnormality determination is not established, and the process returns to step S100.

Steps S130, S140, and S150 are equivalent to steps S20, S30, and S40 described above, respectively, and perform the same processing in each step. Furthermore, steps S160, S170, and S180 are equivalent to steps S50, S60, and S70 described above, respectively, and perform the same processing in each step. Further, after step S180, the abnormal detection control is ended, and the process returns to step S100.

Advantages of the evaporative fuel purge system 201 of the third embodiment are described. The evaporative fuel purge system 201 determines whether or not the abnormality determination circuit should perform the abnormality determination according to the concentration of the evaporated fuel detected by the concentration detector. For example, the concentration of evaporative fuel flowing from the canister 12 through the purge passage 16 is calculated by the abnormality determination circuit 30. [

When the concentration of the evaporative fuel is equal to or less than the first threshold value, it is determined that the execution condition of the abnormality determination is established in step S120. Therefore, when the concentration of the evaporative fuel in the purge passage 16 is low, an abnormality is determined. Therefore, the influence of the evaporated fuel on the outside can be reduced. For example, even when leakage actually occurs in the purge passage 16, an abnormality determination that limits the influence on the environment can be performed.

The abnormality determination circuit 30 executes the abnormality determination when the remaining amount of the evaporated fuel in the canister is less than the second threshold value based on the concentration of the evaporated fuel flowing out of the canister 12 and flowing through the purge passage 16 It is judged that the condition is established. Therefore, the influence of the evaporated fuel on the outside can be made similar to the case where the concentration of the evaporated fuel is less than the first threshold value.

As mentioned above, in this embodiment, a differential pressure sensor is used as the concentration detector. In addition, other detectors may be used that detect the concentration using an O ₂ sensor, contact combustion, infrared radiation, gas thermal conduction, and ultrasound. By disposing such a concentration detector in place of the concentration detector 5, it is possible to obtain the same advantage as in the case of using the differential pressure sensor.

(Fourth Embodiment)

The evaporative fuel purge system 301 according to the fourth embodiment will be described with reference to Figs. 10 and 11. Fig. In the fourth embodiment, the same structure, function, and effect as the above embodiment are not described.

The evaporative fuel purge system 301 can supply the evaporative fuel of the purge passage 16 to the intake passage 210 by the intake pressure in the internal combustion engine 2. [ Therefore, in the evaporative fuel purge system 301, the evaporative fuel can be purged by the negative pressure of the intake air in the internal combustion engine 2 with the pump device 13 stopped.

As shown in FIG. 10, the evaporative fuel purge system 301 has a purge control valve 6. The purge control valve 6 is an opening and closing part for opening and closing the purge passage 16, that is, the passage for supplying the evaporative fuel, and can allow and block the supply of the evaporative fuel from the canister 12 to the internal combustion engine 2 . The purge control valve 6 may be, for example, an electromagnetic valve including a valve body, an electromagnetic coil, and a spring.

The control device 3 controls the valve opening degree of the purge control valve 6. The purge control valve 6 can allow and block the supply of evaporative fuel from the canister 12 to the suction portion 141. [ The purge control valve 6 opens and closes the passage for supplying the evaporative fuel according to a balance between the electromagnetic force generated when current is supplied to the coil and the biasing force of the spring.

Normally, the purge control valve 6 maintains a state in which the passage for supplying the evaporative fuel is closed. When the electromagnetic coil is energized by the control device 3, the electromagnetic force is larger than the biasing force of the spring, so that the passage for supplying the evaporative fuel is opened. Furthermore, the control apparatus 3 energizes the coil by controlling the duty ratio, that is, the ratio of the on-time for one cycle, which is constituted by the on-time and the off-time. The purge control valve 6 is also referred to as a duty control valve. Therefore, the flow rate (purge amount) of the evaporating fuel flowing through the passage for supplying the evaporating fuel can be adjusted. Furthermore, the pump device 13 may have a structure to prevent the inflow of outside air at the time of stoppage. The external fluid passage 17 may have a valve structure that prevents inflow of external air when the pump apparatus is stopped.

In the fourth embodiment, the first purge passage 16a includes a first purge passage 16a1 between the canister 12 and the purge control valve 6, and a second purge passage 16b1 between the purge control valve 6 and the suction portion 141 And is formed separately as the third purge passage 16c. Therefore, when the purge control valve 6 is closed, the evaporative fuel can not flow into the third purge passage 16c from the first purge passage 16a1.

The flow rate (purge amount) of the evaporative fuel supplied from the purge passage 16 to the intake passage 210 is controlled so as to satisfy the required purge amount (hereinafter referred to as the demand amount or the required value) required from the vehicle. Therefore, when the required amount can not satisfy the purging amount due to the negative pressure of the intake air in the internal combustion engine 2, the evaporation fuel is supplied using the pump device 13 and the ejector device 14.

11 shows a flow chart for explaining the flow rate control in which the negative pressure of the intake air by the internal combustion engine 2 and the air pumping by the pump device 13 are combined. As shown in Fig. 11, the control device 3 performs a plurality of control methods according to the range of the negative pressure (intake manifold pressure) of the intake air of the internal combustion engine 2 in order to satisfy the purge demand amount. This control device 3 obtains information on the required amount from the vehicle ECU, and this required amount can be changed in accordance with the degree of opening of the throttle valve 23.

In the region where the negative pressure of the intake air of the internal combustion engine 2 is large, the maximum purging amount of the negative pressure exceeds the required amount, so that the control device 3 controls the valve opening degree of the purge control valve 6 by the above- Thereby controlling the purge amount. Furthermore, the maximum purge amount of sound pressure is stored in advance as a map in a memory such as a ROM and a RAM. The controller 3 calculates the maximum purging amount of the current sound pressure using the acquired intake manifold pressure and the map.

In the region where the maximum purging amount of the sound pressure is smaller than the required amount, the negative pressure of the intake air of the internal combustion engine 2 is small, so that the controller 3 outputs the output of the pump device 13 and the valve opening of the purge control valve 6 To control the purge amount.

In the region where the negative pressure of the intake air of the internal combustion engine 2 can not be obtained, the purge amount satisfying the required amount is controlled by controlling the output of the pump device 13 with the valve opening degree of the purge control valve 6 being set at the maximum do. Therefore, in this area, the required amount is secured by the performance of the pump device 13 and the performance of the ejector device 14. [

(Fifth Embodiment)

The evaporative fuel purge system 401 according to the fifth embodiment will be described with reference to Fig. In the fifth embodiment, the same structure, function, and effect as the above embodiment are not described.

This evaporative fuel purge system 401 is a combination of the system of the second embodiment, the system of the third embodiment, and the system of the fourth embodiment. Therefore, the evaporative fuel purge system 401 can supply the evaporative fuel of the purge passage 16 to the intake passage 210 by the manifold air pressure of the internal combustion engine 2.

In the evaporative fuel purge system 401, when there is an abnormality such as a leak in the target passage, the evaporated fuel that is filled in the target passage necessarily leaks. The target passage is provided with a vapor passage 15, a first purge passage 16a, a second purge passage 16b, a concentration detector 5, a purge control valve 6, a fuel tank 10, a canister 12, Device 14, an external fluid passage 17, a sub-canister 19, and a bi-directional rotary pump 113.

The evaporative fuel purge system 401 has an abnormality determination function for detecting a leak and determining that an abnormality has occurred in the purge system. Therefore, the control apparatus 3 performs basic control such as fuel purging in the evaporative fuel purge system 401, and also judges an abnormality in the system by the abnormality determination circuit 30. [ The abnormal detection control is the same as that of the second embodiment and the third embodiment. When the abnormality is detected, the purge control valve 6 is controlled to the open state.

(Other Embodiments)

The present invention is not limited to the above embodiment within the scope of the present invention, but can be variously modified.

The structure of the above embodiment is merely an example, and the technical scope of the present invention is not limited to the disclosed range. The technical scope of the present invention is indicated by the claims, and includes all changes within the meaning and scope equivalent to those of the claims.

The check valve 4 may be replaced with an electromagnetic valve that opens and closes the passage. In this case, the electromagnetic valve may be a valve device controlled to an open state for opening the passage when no voltage is applied, and to a closed state for closing the passage when a voltage is applied.

In the system of the third embodiment, it is preferable to execute an abnormality determination in a state where the internal combustion engine 2 is stopped. However, the system of the third embodiment can execute an abnormality determination while the internal combustion engine 2 is in operation.

The check valve 4 may be replaced with an electromagnetic valve that electrically opens and closes the passage. In this case, the electromagnetic valve may be a valve device controlled to an open state for opening the passage when no voltage is applied, and to a closed state for closing the passage when a voltage is applied.

When the abnormality determination circuit 30 determines whether or not an abnormal condition is established, the internal pressure of the fuel tank 10 is not used, and the pressure detected by the pressure sensor at an arbitrary position in the purge passage 16 Can be used.

In the second, third, and fifth embodiments, the evaporative fuel purge system supplies the evaporative fuel of the purge passage 16 to the intake passage 210 by the manifold air pressure of the internal combustion engine 2 And it is possible to detect an abnormality such as leakage in the object passage.

The abnormality determination circuit 30 can determine whether or not an abnormal condition is established by the following method. 5, 6, and 7, the control device 3 stores, as a map, a change in normal time and a change in abnormal time in the memory, for example. In this case, the abnormality determination circuit 30 determines whether the abnormality condition is established by determining whether the detected data is close to which of the normal map and the abnormal map.

Such changes and modifications are to be understood as being within the scope of the invention as defined by the appended claims.

Claims (7)

As the evaporative fuel purge system,
A fuel tank for storing fuel;
A canister capable of adsorbing the evaporative fuel and releasing the evaporative fuel when the evaporative fuel is discharged from the fuel tank;
An intake passage of an internal combustion engine in which the evaporated fuel desorbed from the canister is mixed with fuel for combustion;
A purge passage connecting the canister to the intake passage;
A purge passage disposed in the purge passage,
A nozzle unit for accelerating the external fluid to be introduced,
A suction unit for sucking the evaporative fuel from the canister by a suction force generated by the external fluid ejected from the nozzle unit,
An ejector device having a diffuser portion for emitting a mixture of the external fluid ejected from the nozzle portion and the evaporation fuel drawn from the suction portion toward the intake passage; And
And a fluid drive device for transferring outside air corresponding to the external fluid into the nozzle portion. The method according to claim 1,
Wherein the fluid drive device is capable of transferring fluid in the purge passage to the outside,
A valve device capable of allowing the evaporated fuel discharged from the diffuser portion to flow into the intake passage from the purge passage and preventing fluid from flowing backward from the intake passage to the purge passage; And
Further comprising an abnormality determination circuit for determining an abnormality of the purge passage in a state in which the fluid drive device sucks the fluid of the purge passage to the outside,
Wherein the abnormality determination circuit detects a predetermined physical quantity related to a pressure change in the target passage including the purge passage and determines an abnormality of the evaporative fuel purge system in accordance with the predetermined physical quantity. 3. The method of claim 2,
The evaporative fuel purging system comprises:
Further comprising a sub-canister for adsorbing evaporative fuel from the fluid in the purge passage drawn by the fluid drive apparatus. The method according to claim 2 or 3,
Wherein the valve device is not disposed in a duct forming the purge passage but is disposed in a duct member forming the intake passage. The method according to claim 2 or 3,
Wherein the predetermined physical quantity is an internal pressure of the fuel tank. The method according to claim 2 or 3,
Wherein the predetermined physical quantity is at least one of a power consumption, a consumption current, a consumption voltage and a drive cycle of the fluid drive apparatus. The method according to claim 2 or 3,
The evaporative fuel purging system comprises:
Further comprising a concentration detector disposed in the subject passage including the purge passage for detecting the concentration of the evaporated fuel,
And the abnormality determination circuit executes a determination to detect an abnormality based on the concentration of the evaporated fuel detected by the concentration detector.

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